This invention relates to a device for measuring the quantity of electric charges on an electrified fluid and more particularly to such a device used with electrically nonconducting fluid, for example, petroleum.
When an electrically nonconducting fluid such as petroleum is accumulated in a reservoir after flowing through a pipe line, electric charges occur in the fluid due to friction between particles thereof and between the fluid and the adjacent pipe wall. When the fluid thus electrified is accumulated in the reservoir, the sum of electric charges amounts to a considerable quantity. If the electric charges discharge within the reservoir for any reason, this may result in an accident such as an explosion. Therefore it is required to measure the total quantity of electric charges and prevent the occurrence of such an accident by using a charge neutralizer or any other means. This results in the necessity of measuring the quantity of electric charges on electrified flowing fluids.
To this end, there has been already been developed what is called a probe method. The probe method uses, as a probe, a small metallic sphere connected to an electrostatic voltmeter. When the sphere is placed in an electrified fluid to be measured, it acquires electric charges until its potential is equal to that of the fluid. Then the potential of the fluid is measured by the electrostatic voltmeter and the quantity of electric charges in the fluid is calculated. However, from other precise experiments it has been found that conventional probe methods such as described above do not give an accurate potential of the sphere particularly with flowing fluids of low electric conductivity. This is because the particular flowing fluid collides violently with the sphere resulting in great friction therebetween until electric charges are developed on the sphere itself. Also there have been the disadvantages that electrostatic voltmeters are, in many cases expensive and can not carry out an accurate measurement unless experts handle them.
Accordingly, it is an object of the present invention to provide a new and improved device for simply measuring a quantity of electric charges in a flowing electrified fluid with a high accuracy.